SARVAJANIK COLLEGE OF ENGINEERING & TECHNOLOGY Gyratory crusher Prepared by: Joshi chirag - 130420105023 Joshi kaushik - 130420105024 Kala juhi - 130420105025 Kachhadiya mayur - 130420105026

CONTENT Introduction to size reduction Classification of equipments Types of crusher Gyratory crusher Operating principal of gyratory crusher Construction Working Control of crushers Application

Before we study what are the equipments used for size reduction, lets understand why “SIZE REDUCTION”

In the chemical industries, the size reduction is carried out for a variety of reasons.. A few of which are: To increase the surface area because in most chemical reactions the rate is proportional to the area of contact between the two phases. To have an effective separation To meet the customers need To have proper mixing. A great variety of size reduction equipments are employed for this purpose and they work on any one or a combination of the four actions : compression , impact, shear and attrition.

Size Reduction The term size reduction refers to decrement or the process of decreasing of size. Thus, size reduction refers to the process of converting the object from one physical dimension of higher order to another dimension of smaller order. “COMMINUTION” is another term for size reduction.

NOW, what mechanical equipments are used for size reduction?

Classification of size reduction equipments: On the basis of : The mode of operation The method by which a force is applied The size of feed and product.

Size reduction on the basis of size of feed and product Coarse crushers/primary crushers: Large feed size(1 m) and product size(2 cm). This is the requirement of feed size and product in gyratory crushers. Hence, they are basically know as PRIMARY CRUSHERS.

Method by which a force is applied can be further classified into : Impact Compression‘ Attrition Shear

Size reduction by means of compression : Here, the particle is broken by two forces and the size reduction is done between two surfaces with the work being done by one or both surfaces. Compression between two solid surfaces Grinding Crushers As a mechanical reduction method compression is chosen if : The material is hard and tough If the material is abrasive

GYRATORY CRUSHERS uses this method of size reduction because it is suitable for reducing extremely hard and abrasive materials and the finished product is to be relatively coarser in size.

What is crusher? A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust. Crushers may be used to reduce the size, or change the form, of waste materials so they can be more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials (as in rock ore), so that pieces of different composition can be differentiated.

Types of crusher Jaw crusher Gyratory crusher Cone crusher Compound crusher Mineral sizers

Operating principle Gyratory crusher works on principle of compressive force for size reduction.

Gyratory crusher

Construction The gyratory crusher consists of two vertical conical shells, the outer shell having its apex in downward direction will the inner cone is positioned with its apex upward. The inner shell acts as the crushing head, which is in the form of a truncated cone and is mounted on an oscillary shaft. The upper end of this corn is held in a flexible beraring will the lower end is connected to an eccentric.

Construction The eccentricity causes the conical crushing head to oscillate between open side setting(oss) and close side setting(css) discharge openings. Hence, the crushing acting takes place around the whole of cone and is continuous. The eccentricity also determines the capacity of gyraytory crushers.

Construction Primary crushers have a steep cone angle and a small reduction ratio. Secondary crushers have a wider cone angle; this allows the finer product to be spread over a larger passage area and also spreads the wear over a wider area. Wear occurs to the greatest extent in the lower, fine-crushing zone.

Construction These features are further extended in cone crushers; therefore secondary gyratories are much less popular than secondary cone crushers, but they can be used as primaries when quarrying produces suitable feed sizes. The three general types of gyratory crusher are the suspended-spindle, supported-spindle, and fixed-spindle types.

Working Crushing occurs through the full cycle in a gyratory crusher, and this produces a higher crushing capacity than a similarsized jaw crusher, which crushes only in the shutting half of the cycle. Gyratory crushers also tend to be easier to operate. They operate most efficiently when they are fully charged, with the main shaft fully buried in charge.

Working Power consumption for gyratory crushers is also lower than that of jaw crushers. These are preferred over jaw crushers when capacities of (900 tons/h) or higher are required. Gyratories make a product with open-side settings of 5 to 10 in at discharge rates from 600 to 6000 tons/h, depending on size.

Working Most manufacturers offer a throw from 1⁄4 to 2 in. The throughput and power draw depend on the throw and the hardness of the ore, and on the amount of undersized material in the feed. Gyratory crushers that feature wide-cone angles are called cone crushers.  throughput is the rate of production or the rate at which something can be processed. 

Control of Crushers The objective of crusher control is usually to maximize crusher throughput at some specified product size, without overloading the crusher. Usually only three variables can be adjusted: 1)feed rate 2)crusher opening 3)feed size in the case of a secondary crusher.

Control of Crushers Four modes of control for a crusher are: 1. Setting overload control, where the gape setting is fixed except that it opens when overload occurs. 2. Constant power setting control, which maximizes throughput. 3. Pressure control, which provides settings that give maximum crusher force, and hence also throughput. 4. Feeding-rate control, for smooth operation.

Application Gyratory crusher is mainly used in Heavy mining, Quarried materials Mining operations use gyratory crushers.

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